Targeted drug stops tumor growth in patients with early breast cancer

Giving women palbociclib – already hailed as a major step forward in treating advanced breast cancer – alongside hormone therapy had a much greater effect on cell growth than the hormone treatment alone.

Palbociclib, a cyclin-dependent Kinase 4/6 (CDK4/6) inhibitor, alongside an aromatase inhibitor – a type of hormone treatment – shrank tumors in half of women with early-stage disease, a similar proportion to women who took the hormone therapy alone. But the drug combination led to a marked decrease in cell growth, stopping tumor growth entirely in 90% of women, compared with 59% given hormone therapy alone.

The large international trial was led by a team at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, in collaboration with researchers in the USA. It was funded by the drug’s manufacturer, Pfizer (NYSE: PFE), which markets the drug as Ibrance, and posted third-quarter sales of $1.13 billion for its product.